1. Field of the Invention
The present invention relates to a wind power generation system.
2. Description of the Related Art
Wind power generation systems have been introduced widely as a pillar of the renewable energy technology. Wind power generation systems generate power by transmitting the rotating power of blades via the rotation of a hub, which supports the blades, to a main shaft and thereby rotating a generator.
A conventional wind power generation system is described in JP 2001-200781 A, for example. In this document, a nacelle houses a hub that supports blades and rotates with the blades, an elongated rotary main shaft that is located at the inner diameter side of the hub and is connected to the hub through an elastic coupler, a gearbox that is connected to the elongated rotary main shaft, and a generator that receives the rotating power with a speed increased by the gearbox.
In JP 2001-200781 A, the rotary main shaft can be elongated because the shaft is not subjected to bending stress due to the weight of the rotor.